1. Field of the Invention
The present invention relates to the separation of a liquid mixture into its aqueous and non-aqueous liquid phases. More particularly, the invention is related to the separation of the aqueous and non-aqueous phases of a finish composition diluted with water and having a Brookfield viscosity at 25.degree. C. of 2 to 115 centipoise.
2. The Prior Art
In the production of multifilament synthetic polymer yarn, especially polyester and polyamide yarns, it is conventional to coat the solidified filaments with a spin finish or overfinish composition to improve processing of the yarn and ultimate yarn properties. These finish compositions may be applied to the yarn in a variety of ways, for example by contact with a roll rotating in a trough of the composition or with a surface to which the composition is metered. The waste finish composition is diluted with distilled or deionized water for removal from the process equipment and then fed to a collection point for disposal. There may be components of the non-aqueous phase of the waste finish composition which require disposal of the composition in a hazardous waste disposal facility approved by the Environmental Protection Agency. As the water content of the waste finish composition may be quite high, for example as high as 99 percent, it is desirable to develop a method to separate the aqueous and non-aqueous phases for disposal of the non-aqueous phase; transportation and disposal costs necessary for ultimate disposal of the waste would accordingly be greatly decreased.
FIG. 1 of British Patent Specification No. 1,019,099 to Snia Viscosa, hereby incorporated by reference, describes apparatus (a rotary dryer) similar to that used in practicing the method of the present invention. U.S. Pat. Nos. 3,870,475 and 3,787,481, both to Siclari et al., and 3,296,709 to Barsch, all of which are hereby incorporated by reference, also describe apparatus that have potential use for practicing the method of the present invention, specifically a vertical wall evaporator with a high speed rotor and a rotating drum chip dryer, respectively.